An electric vehicle moves by rotating its motor using electricity stored in a battery. Such electric vehicle was developed before of the development of a typical vehicle using an internal combustion engine. However, practical limitations of the electrical vehicle caused by the weight and the time required to charge its battery hindered the full commercialization of the electric vehicle. But, the environmental concerns of using the internal combustion engine have revitalized a further development of the electric vehicle.
The electric vehicle is similar to other typical vehicles with internal combustions engines except that it has an electric motor instead of a combustion engine. Unlike a typical vehicle, an important issue of the electric vehicle development is to reduce the size and the weight of the battery corresponding to its energy source. Particularly, reducing the time required to charge the battery is a critical element for the full commercialization of the electric vehicle.
Accordingly, in a case of an electric vehicle, battery management (i.e., an electric charging management) is very important in operating the electric vehicle. In practice, users may not be able to operate an electric vehicle or may have to wait for a long time if the battery management is not properly performed.
Typically, users check a remaining battery power amount through a battery gauge of an electric vehicle. Such typical way has a limitation. For example, users are not able to check a remaining battery power amount when the electric vehicle (particularly, an electric motor of the electric vehicle) is off, or when the users are outside of the electric vehicle.
The development of telematics technology allowed users to control an electric vehicle or check the status of the electric vehicle through external devices. For example, users may check the status of the battery or the remaining power amount of the battery through wireless devices (e.g., a smart phone). However, such scheme using the telematics technology may require the electric vehicle to have an additional device to communicate with the wireless devices of the users, and this may cost more to users. Furthermore, when users do not carry or have such wireless devices, users may be no longer able to check the status or the remaining power amount of the battery.